The hosts led 25-18 at the break through two Juan Imof tries and one from Luc Ducalcon.

But Saracens hit back after the break with Farrell converting Chris Wyles’ try and kicking ten penalties in all to leave Saracens six points clear of Racing at the top.

Tom Williams grabbed two tries as Harlequins qualified for the quarter-finals thanks to their bonus point 47-8 win over Connacht. Ugo Monye, George Lowe and Ben Botica also crossed with a penalty try awarded.

Toulon join Quins after running in seven tries in their 45-25 win over Cardiff Blues, Jonny Wilkinson kicking four conversions.